Nano-engineering thermal transport performance of carbon nanotube networks with polymer intercalation: a molecular dynamics study

Abstract

Based on polymer perfusion behaviour inside carbon nanotube (CNT) networks, the thermal transport performances of the CNT networks with various extents of polymer intercalation are studied by dividing them into two parts: thermal transport at the tube contact interfaces of CNT junctions and along the tube axis. The thermal transport performance at the tube contact interfaces of CNT junctions is similar to that in the transverse direction of graphene layers. Hence, to obtain a fundamental understanding of thermal transport performance at the tube contact interfaces, thermal conductance along the z-axis direction of graphene layers with and without polymer intercalation is investigated using a non-equilibrium molecular dynamics (MD) simulation method. Thermal conductivity along the tube axis direction of the polymer wrapped CNT is also calculated using the same method. The simulation results show that a low extent of polymer aggregation at the tube contact interfaces can significantly improve the interfacial thermal conductance. However, when the polymer content at the tube contact interfaces exceeds a critical fraction, the interfacial thermal conductance is decreased. The results also indicate that the polymer molecules wrapping around the CNT walls have a strong negative influence on the bulk thermal conductivity of the CNT along its axis direction.